The subject matter disclosed herein relates generally to imaging, such as voltage or current injected electrical impedance tomography and/or magnetic induction tomography.
Electrical impedance tomography (EIT) is a medical imaging technique used to non-invasively probe the internal properties of an object or subject, such as the electrical properties of materials or internal structures within the object or subject. For example, in EIT systems, an estimate of the distribution of electrical conductivities of probed internal structures is made and utilized to reconstruct the conductivity and/or permittivity of the materials within the probed area or volume. In certain implementations, electrodes are used to apply an alternating current (or a voltage in other implementations) to the surface of the skin and the resulting potential is measured. Measurements are made from different points on the skin and an image of impedance within the body is created using image reconstruction techniques. Thus, electrical impedance tomography provides imaging information regarding the internal electrical properties inside a body based on voltage measurements made at the surface of the body.
Electrical impedance tomography is a non-invasive technique for imaging physiological and pathological body functions. The benefits of EIT applications in medicine lie in the possibility of obtaining high temporal resolution, and in the portability and limited cost of the scanner. The main limitation is the low spatial resolution, which is due to the reconstruction problem being generally ill-posed. The underlying principle is to exploit the electrical properties of biological tissues to extract information about the anatomy and physiology of organs. The physical parameter of interest in EIT is the complex impedance or real conductivity that, in the case of biological tissue, are frequency dependent. A small amount of current (or a voltage) is injected into the body and voltage measurements are acquired using peripheral electrodes. A reconstruction algorithm is implemented to image the impedance distribution of the subject in two or three dimensions.